[14.17] About the same time a trifling
beginning led to frightful bloodshed between the inhabitants of Nuceria
and Pompeii, at a gladiatorial show exhibited by Livineius Regulus, who
had been, as I have related, expelled from the Senate. With the unruly
spirit of townsfolk, they began with abusive language of each other; then
they took up stones and at last weapons, the advantage resting with the
populace of Pompeii, where the show was being exhibited.

And so there were
brought to Rome a number of the people of Nuceria, with their bodies mutilated
by wounds, and many lamented the deaths of children or of parents. The
emperor entrusted the trial of the case to the Senate, and the Senate to
the consuls, and then again the matter being referred back to the Senators,
the inhabitants of Pompeii were forbidden to have any such public gathering
for ten years, and all associations they had formed in defiance of the
laws were dissolved. Livineius and the others who had excited the disturbance,
were punished with exile.

However, the consensus is that the theatre most likely re-opened after less than ten years. Bill ThayerJim Grout has a page with a spectacular fresco depicting the riot.

The theatre was destroyed during the eruption of Mt. Vesuvius in AD 79, but seems to have been reopened in some form thereafter.

[14.17] About the same time a trifling
beginning led to frightful bloodshed between the inhabitants of Nuceria
and Pompeii, at a gladiatorial show exhibited by Livineius Regulus, who
had been, as I have related, expelled from the Senate. With the unruly
spirit of townsfolk, they began with abusive language of each other; then
they took up stones and at last weapons, the advantage resting with the
populace of Pompeii, where the show was being exhibited.